Validity and reliability of rapidly alternating movement tests

Two studies investigated the interrater reliability and concurrent validity of tests of rapidly alternating movement. Study I examined the interrater reliability of three different tests, "finger tapping" to the adjacent thumb, "table tapping," and "hand to thigh" alternating movements. Using normal participants the results indicated poor interrater agreement for the "hand to thigh" test and modest relationship for both types of finger tapping. However, for each test the number of recorded repetitions differed significantly between raters. Study 2 examined the concurrent validity of two mechanical measures of finger tapping. The scores of 36 normal participants was compared using a mechanical digital counter and a calculator. Results indicated that the use of the calculator as a counter was highly related to the results with a mechanical digital counter. Conclusions suggested the use of a mechanical apparatus is more reliable than human observations. In addition, the use of an inexpensive apparatus will produce results similar to the manual finger tapping apparatus commonly used in neuropsychological batteries.

Boundary Effects on Electrophoretic Motion of Spherical Particles for Thick Double Layers and Low Zeta Potential

The electrophoretic motion of a charged sphere in the presence of a rigid boundary is analyzed for low surface zeta potentials but arbitrary kappaa, where a is the particle radius and kappa is the inverse Debye length. The boundary configurations considered are a single flat wall, a slit, and a long cylindrical tube. Using a method of reflections, we obtain the particle velocity for a constant applied electric field in powers of lambda up to O(lambda6), where lambda is the ratio of the particle radius to the distance from the boundary. This analysis is valid as long as the double layer around the particle does not overlap significantly with the double layer at the boundary. The effect of finite kappaa is to enhance the viscous retardation of the particle, although for large separations the first effect due to the proximity of the boundary is still at O(lambda3) in all cases. When the applied field is parallel to the boundary, the electrophoretic velocity is not proportional to the difference in zeta potential between the particle and the boundary (as occurs for kappaa --> infinity), and the proximity of the boundary may increase the particle velocity or change its direction. An important result of the analysis is that the hindrance to the electrophoretic velocity of a particle in a cylindrical pore increases significantly as kappaa is reduced below 10.

Inducing practice guidelines from a hospital database

Improving health care quality requires the elimination of unnecessary variation in the care process. Decision support applications already exist that can foster adherence to standards. The challenge resides in developing standards consistent with good medical practice. In this paper we present our efforts in determining where sufficient clinical data are captured electronically to automatically define a care process, and what analyses can be done to identify additional data that would allow a care process to be defined. Data routinely collected by a hospital information system have been examined. The analysis tools utilized include logistic regression, a neural network, a Bayesian network, and a rule induction program.

Impact of the Food and Drug Administration approval of flecainide and encainide on coronary artery disease mortality: putting "Deadly Medicine" to the test

In his book Deadly Medicine and on television, Thomas Moore impugns the process of antiarrhythmic drug approval in the 1980s, alleging that the new generation of drugs had flooded the marketplace and had caused deaths in numbers comparable to lives lost during war. To assess these important public health allegations, we evaluated annual coronary artery disease death rates in relation to antiarrhythmic drug sales (2 independent marketing surveys). Predicted mortality rates were modeled using linear regression analysis for 1982 through 1991. Deviations from predicted linearity were sought in relation to rising and falling class IC and overall class I antiarrhythmic drug use. Flecainide came to market in 1986 and encainide in 1987. Combined class IC sales peaked in 1987 and 1988 (maximum market penetration, 20%, first quarter 1989). Results of the Cardiac Arrhythmia Suppression Trial (CAST) were disclosed in April 1989. Overall annual class I antiarrhythmic prescription sales actually fell slightly (-3% to -4%/yr) in the 2 years before CAST and then more abruptly (- 12%) in the year after CAST (1990). Sales of class IC drugs fell dramatically after CAST (by 75%). Coronary death rates (age adjusted) fell in a linear fashion during the decade of 1982 through 1991. No deviation from predicted rates was observed during the introduction, rise, and fall in class IC (and other class I) sales: rates were 126/100,000 in 1985 (before flecainide), 114 and 110 in 1987 and 1988 (maximum sales), and 103 in 1990 (after CAST). Deviations in death rates in the postulated range of 6,000 to 25,000 per year were shown to be excluded easily by the 95% confidence intervals about the predicted rates. Entry of new antiarrhythmic drugs in the 1980s did not lead to overall market expansion and had no adverse impact on coronary artery disease death rates, which fell progressively. Thus, the allegations in Deadly Medicine could not be confirmed.

An in vivo mutation from leucine to tryptophan at position 210 in human immunodeficiency virus type 1 reverse transcriptase contributes to high-level resistance to 3'-azido-3'-deoxythymidine

Sequencing of the reverse transcriptase (RT) region of 26 human immunodeficiency virus type 1 (HIV-1) isolates from eight patients treated with 3'-azido-3'-deoxythymidine (AZT) revealed a mutation at codon 210 from TTG (leucine) to TGG (tryptophan) exclusively in association with resistance to AZT. The mutation Trp-210 was observed in 15 of the 20 isolates phenotypically resistant to AZT, being more commonly observed than resistance-associated mutations at codons 67, 70, and 219. Trp-210 was never observed before the emergence of resistance-associated mutations Leu-41 and Tyr-215, and in a sequential series of five isolates from one patient the order of emergence of mutations was found to be Tyr-215, Leu-41, and then Trp-210. Trp-210 was also found in association with the Leu-41, Asn-67, Arg-70, and Tyr-215 resistance genotype. To define the role of Trp-210 in AZT resistance, molecular HIV-1 clones were constructed with various combinations of RT mutations at codons 41, 67, 70, 210, and 215 and tested for susceptibility to AZT. In clones with polymerase genes derived either from HXB2-D or clinical isolates, Trp-210 alone did not increase AZT resistance, whereas in conjunction with Leu-41 and Tyr-215, Trp-210 contributed to high-level resistance (50% inhibitory concentration of >1 microM). In HXB2-D, Trp-210 with Tyr-215 generated a virus with resistance comparable to one with Leu-41, Tyr-215, and Trp-210. Inserting Trp-210 into the genetic context of mutations at codons 41, 67, 70, and 215 further enhanced resistance from a 50% inhibitory concentration of 1.44 microM to 8.41 microM. Molecular modeling of the tertiary structure of HIV-1 RT revealed that the distance between the side chains of Trp-210 (in helix alphaF) and Tyr-215 (in strand beta11a) approximated 4 A (1 A = 0.1 nm), sufficiently close to result in significant energetic interaction between these two aromatic side chains. In conclusion, Trp-210 contributes significantly to phenotypic AZT resistance of HIV-1 by augmenting resistance at least three- to sixfold in the context of two resistant genotypes, and its effect may require an interaction with an aromatic amino acid at position 215.

Cytokines and rejection of mouse cardiac allografts

Graft survival is prolonged by pretransplant transfusion of the graft recipient. It has been postulated that graft rejection is associated with Th1-like cytokines. We tested whether transfusion shifts cytokine production from a Th1-type (gamma-IFN production) to a Th2-type (IL-4 production). Transfusion prolonged cardiac allograft (C3H/HeN donor to a C57BL/6 recipient) survival (10.4+/-0.5 versus 7.2+/-0.2 days for controls, P<0.0001). Splenocyte cultures from nontransfused recipients produced supernatant IFN-gamma concentrations of 13.4+/-1.4 ng/ml upon anti-CD3 stimulation; the same cells produced 32.3+/-3.5 pg/ml IL-4 stimulated with Con A. Spleen cells from transfused animals did not produce gamma-IFN with or without stimulation; (P<0.0001) and produced 21.5+/-3.2 pg/ml IL-4 without stimulation (P<0.0001 compared with controls). C57BL/6 CD8+ lymphocytes isolated from rejected C3H grafts were adoptively transferred (6.7+/-1x10(6)/animal) to pretransfused, C57BL/6 recipients of a C3H graft. Graft survival for these recipients was 7.8+/-0.3 days compared with 10.4+/-0.5 days for recipients pretreated with transfusion only (P<0.005). Transcripts of the gamma-IFN gene were present in unmodified grafts but not in the grafts from transfused recipients given the CD8 cells. In conclusion, transfusion downregulated gamma-IFN production and up-regulated IL-4 production and slowed (but did not abrogate) rejection; CD8 graft-infiltrating cells given adoptively restored normal rejection but not IFN-gamma. Further studies are needed to elucidate the role of cytokines in cardiac allograft rejection.

Explaining discrepant mortality results between primary percutaneous transluminal coronary angioplasty and thrombolysis for acute myocardial infarction

Differing relative outcomes in randomized versus registry studies comparing primary angioplasty with thrombolytic therapy for acute myocardial infarction suggest a clinical paradox. A predictive model based on differences in 5 treatment-related factors, including time to therapy, patency success, and angioplasty experience, suggests that relative outcomes may indeed vary, depending on the clinical setting in which therapy is given.

Safety and tolerability of long-term propafenone therapy for supraventricular tachyarrhythmias. The Propafenone Multicenter Study Group

An important issue regarding the long-term use of antiarrhythmic drugs concerns the safety of these agents, particularly with regard to cardiac toxicity. Propafenone is an effective drug for preventing supraventricular tachyarrhythmia, but the incidence of side effects during longterm therapy in patients with such arrhythmias has not been adequately reported. A total of 480 patients received oral propafenone as therapy for symptomatic atrial fibrillation, atrial flutter, or supraventricular tachycardia. During the follow-up (mean 14.4 months), 290 patients (60%) discontinued propafenone therapy, but in only 70 patients (15%) was the reason for discontinuation an adverse drug reaction. Overall, 284 patients (59%) experienced at least 1 adverse reaction, and the incidence was related to dose and age >65 years. The overall incidence of side effects was not related to structural heart disease; however, cardiovascular toxicity including arrhythmia aggravation, congestive heart failure, and serious conduction disturbances occurred more often in those with heart disease (20% vs 13%). Sixteen patients died during drug therapy, but in only 1 case was the drug considered contributory. For patients with a supraventricular arrhythmia, propafenone was well tolerated and was infrequently discontinued because of side effects. The incidence of serious cardiac toxicity when propafenone was used to treat supraventricular arrhythmia was low, and these side effects were more frequent in patients with structural heart disease.

Safety assessment of a nematode-resistant tomato by a simple, short-term rat feeding study

A simple, 11-week, weanling rat feeding period was used to determine general safety of a nematode-resistant tomato cultivar. Comparison of growth, mean blood hemoglobin, hematocrit, red blood cell count, and total white blood cell count of Fisher rats fed a complete diet containing 40% "VFN 8" tomato (nematode-resistant) cultivar to two other groups of rats, fed either a "New Yorker" tomato (nematode-susceptible) or a control diet, showed normal and similar results. Although the expressed product of the Mi gene necessary for nematode resistance is unknown, this short, comparative study of a whole plant food shows no unexpected toxicants influencing animal growth and hematology. However, human exposure of this resistant tomato would be needed to definitely determine consumer safety regarding allergenicity and hypersensitivity.

Metaanalysis of five reported studies on the relation of early coronary patency grades with mortality and outcomes after acute myocardial infarction

Coronary patency has been used as a measure of thrombolysis success after acute myocardial infarction (AMI). The Thrombolysis in Myocardial Infarction (TIMI) study grading scale for coronary perfusion has gained wide acceptance, but the significance of individual grades on clinical outcome has not been adequately tested. We hypothesized that optimal outcomes would be achieved only with early (and maintained) TIMI grade 3 (complete) perfusion compared with TIMI grade 2 (partial perfusion, previously classified as a reperfusion success) or grades 0 or 1 (occluded arteries). Five recent, angiographically controlled, prospectively performed studies of thrombolysis in AMI were identified, representing 3,969 patients. Odds ratios for mortality by early perfusion grades were calculated using the Mantel-Haenszel test and combined in a weighted fashion. Results for selected clinical and laboratory outcomes by patency grade were also assessed. Overall, mortality averaged 8.8% for TIMI grade 0/1, 7.0% for grade 2, and 3.7% for grade 3 perfusion. The odds ratio (OR) for early mortality was substantially reduced for grade 3 versus <3 perfusion (OR = 0.45, confidence interval [CI] 0.34 to 0.61, p <0.0001). In pairwise comparisons, grade 3 was clearly superior to grade 2 (OR = 0.54, CI) 0.37 to 0.78, p = 0.001) as well as grades 0/1 (OR = 0.41, CI 0.30 to 0.56, p <0.0001). Acute and convalescent ejection fraction, regional wall motion, time to enzyme peaks (creatine kinase [CK], creatine kinase myocardial bond [CK-MB]), peak enzyme levels [CK, lactate dehydrogenase [LDH], LDH-1), and risk of heart failure were each significantly less in patients achieving grade 3 than grade 2 (or lower grades) perfusion. Results were observed despite the frequent use of interventions after angiography. This meta-analysis demonstrates that early and complete (grade 3) flow is associated with superior survival and clinical outcome; grade 2 perfusion results in an inferior outcome, closer to that of an occluded than an open artery. The goal of reperfusion strategies should be early and maintained TIMI grade 3 perfusion.

An emergency department-based protocol for rapidly ruling out myocardial ischemia reduces hospital time and expense: results of a randomized study (ROMIO)

OBJECTIVES

We tested the hypothesis that an emergency department-based protocol for rapidly ruling out myocardial ischemia would reduce hospital time and expense but maintain diagnostic accuracy.

BACKGROUND

Patients with a missed diagnosis of myocardial infarction have a high mortality rate; however, providing routine hospital care to low risk patients may not be time- or cost-effective.

METHODS

One hundred low risk patients were entered into the study and randomized either to an emergency department-based rapid rule-out protocol (n = 50) or to routine hospital care (n = 50). Patients receiving routine care were managed by their attending physicians. The rapid protocol included serum enzyme testing at 0, 3, 6 and 9h, serial electrocardiograms with continuous ST segment monitoring and, if results were negative, a predischarge graded exercise test. Study patients were also compared with 160 historical control subjects.

RESULTS

Myocardial infarction or unstable angina occurred in 6% of patients within 30 days; no diagnoses were missed. By intention to treat analysis (n = 50 in each group), the hospital stay was shorter and charges were lower with the rapid protocol than with routine care (p = 0.001). Among patients in whom ischemia was ruled out, those assigned to the rapid protocol had a shorter hospital stay (median 11.9 vs. 22.8 h, p = 0.0001) and lower initial ($893 vs $1,349, p = 0.0001) and 30-day ($898 vs. $1,522, p = 0.0001) hospital charges than did patients given routine care. In historical control subjects, the hospital stay was longer (median 34.5 h, p = 0.001 vs. either group) and charges greater (median $2,063, p = 0.001, vs rapid protocol, p = 0.02, vs. routine care group).

CONCLUSIONS

In low risk patients who present to the emergency department with chest pain, the rapid protocol ruled out myocardial infarction and unstable angina more quickly and cost-effectively than did routine hospital care.

Post-myocardial infarction trials: beta blockers, antiarrhythmics, thrombolytics

This paper reviews trials of postmyocardial infarction therapies including beta adrenergic blockers, antiarrhythmic agents other than amiodarone, and thrombolytic drugs. The results of certain beta blockers on overall cardiovascular mortality and sudden death mortality after myocardial infarction are discussed, along with the results of CAST and subgroup analyses on patients at high risk for death. The effects of thrombolysis during acute myocardial infarction on subsequent arrhythmic mortality are also reviewed.

Increased incidence of Chlamydia species within the coronary arteries of patients with symptomatic atherosclerotic versus other forms of cardiovascular disease

OBJECTIVES

The objectives of this study were to test prospectively for an association between Chlamydia and atherosclerosis by comparing the incidence of the pathogen found within atherosclerotic plaques in patients undergoing directional coronary atherectomy with a variety of control specimens and comparing the clinical features between the groups.

BACKGROUND

Previous work has suggested an association between Chlamydia pneumoniae infection and coronary atherosclerosis, based on the demonstration of increased serologic titers and the detection of bacteria within atherosclerotic tissue, but this association has not yet been regarded as established.

METHODS

Coronary specimens from 90 symptomatic patients undergoing coronary atherectomy were tested for the presence of Chlamydia species using direct immunofluorescence. Control specimens from 24 subjects without atherosclerosis (12 normal coronary specimens and 12 coronary specimens from cardiac transplant recipients with subsequent transplant-induced coronary disease) were also examined.

RESULTS

Coronary atherectomy specimens were definitely positive in 66 (73%) and equivocally positive in 5 (6%), resulting in 79% of specimens showing evidence for the presence of Chlamydia species within the atherosclerotic tissue. In contrast, only 1 (4%) of 24 nonatherosclerotic coronary specimens showed any evidence of Chlamydia. The statistical significance of this difference is a p value < 0.001. Transmission electron microscopy was used to confirm the presence of appropriate organisms in three of five positive specimens. No clinical factors except the presence of a primary nonrestenotic lesion (odds ratio 3.0, p = 0.057) predicted the presence of Chlamydia.

CONCLUSIONS

This high incidence of Chlamydia only in coronary arteries diseased by atherosclerosis suggests an etiologic role for Chlamydia infection in the development of coronary atherosclerosis that should be further studied.

Hyperadrenergic state following acute withdrawal from clonidine used at supratherapeutic doses

Abrupt cessation of clonidine treatment precipitates a physiological withdrawal syndrome, thought to be due to a hyperactive state of central autonomic and cognitive adrenergic neuronal systems dependent on presynaptic alpha 2-adrenoceptors and/or imidazoline receptors. We hereby describe a 36-year-old male with history of end-stage renal disease, hypertension and medication non-compliance, who presented with severe hypertension and remarkable agitation. His daily clonidine intake was estimated to be 10 mg. The patient had abruptly discontinued his clonidine five days prior to admission. The following indices of adrenergic activity were measured in plasma (normal control values in parentheses): noradrenaline (NA) 8.59 nmol/l (1.32-4.56 nmol/l), adrenaline (Adr) 1.86 nmol/l (0.83-4.20) nmol/l), total 3-methoxy-4-hydroxyphenylglycol (MHPG) 152.8 nmol/l (45.1-111.5 nmol/l), and free MHPG 33.0 nmol/l (12.2-31.4 nmol/l). Plasma clonidine level was 3.53 ng/ml (15.9 nmol/l) with the usual therapeutic level being < 2.0 ng/ml (8.9 nmol/l). Initially, the patient received sedatives and was started on clonidine for the first 24 hours only, after which time period prazosin was started, with good response of his blood pressure and reversal of his mental status changes. At that point, the plasma values of indices of adrenergic activity had decreased compared with their corresponding initial values by the following percentages: NA 60.6%, Adr 22.6%, total MHPG 42.2% and free MHPG 11.5%. Plasma clonidine level had decreased now by 43.6% to an absolute value of 1.99 ng/ml (8.85 nmol/l). We emphasize that physicians should be aware of clonidine's abuse potential and caution should be taken, as well as the appropriate route chosen, when prescribing clonidine in patients who show features of poor compliance to medications and especially in patients with psychoses, suicide potential or personality disorders.

Regulation of hamster alpha 1B-adrenoceptors expressed in Chinese hamster ovary cells

Chinese hamster ovary (CHO) cells were stably transfected to express the hamster alpha 1B-adrenoeceptor, and the function and agonist-induced regulation of the binding properties of these receptors were characterized. The cells expressed approximately 230,000 receptors per cell, with a KD for [3H]prazosin of 140 pM. In assays of competition by epinephrine for [3H]prazosin binding to receptors on intact cells, 88% of the receptors were in a low affinity form. The protein kinase C activator phorbol 12-myristate, 13-acetate (PMA) did not further increase the fraction in the low affinity form, but the protein kinase C inhibitor staurosporine reduced the low affinity fraction to 51%. In sucrose density gradient centrifugation assays of receptor internalization, the percentage of receptors in the light vesicle fraction was 25% for control cells, 53% for epinephrine-pretreated cells, 44% for PMA-pretreated cells, and 53% for cells pretreated with epinephrine plus PMA. Staurosporine completely blocked PMA-induced internalization, but only partially inhibited epinephrine-induced internalization. These results suggest a relationship between low affinity binding and internalization for alpha 1B-adrenoceptors and the involvement of protein kinase C in both processes. Longer-term (24 h) exposure of cells to epinephrine induced an unexpected up-regulation of receptor density of approximately 2-fold that was accompanied by an increase in maximal agonist-stimulated phosphoinositide turnover. These studies document several regulatory differences between alpha 1B-adrenoceptors expressed in transfected CHO cells and those natively expressed in DDT1 MF-2 hamster smooth muscle cells, and they provide additional information on the molecular mechanisms involved in agonist-induced regulation of alpha 1B-adrenoceptors.

Partitioning and diffusion of proteins and linear polymers in polyacrylamide gels

The equilibrium partition coefficient (K) and diffusion coefficient (Dgel) of two proteins and two linear polymers were measured as a function of polymer content of a 2.7% cross-linked polyacrylamide (PA) gel. The gel concentration, expressed as a volume percentage of PA in the gel (phi), varied between 0 and 14%. The measurements were made by fluorescence spectroscopy; fluorescent dyes were covalently attached to the macromolecules. The dependence of K on phi for the proteins agrees with a model of the gel network as randomly placed, impenetrable rods. The diffusion data are interpreted in terms of an effective medium theory for the mobility of a sphere in a Brinkman fluid. Using values of the Brinkman parameter in the literature, the effective medium model with no adjustable parameters fits the diffusion data for the proteins very well but underpredicts Dgel for the linear polymers. The gel effect on partitioning is significantly greater than that on diffusion. The permeability (KDgel) of bovine serum albumin decreased by 10(3) over the range phi = 0 --> 8%, and the ratio of permeabilities for ribonuclease compared to BSA increased from 2 to 30.

Development of an in vivo model of human multiple myeloma bone disease

Osteolytic bone destruction and its complications, bone pain, pathologic fractures, and hypercalcemia, are a major source of morbidity and mortality in patients with multiple myeloma. The bone destruction in multiple myeloma is due to increased osteoclast (OCL) activity and decreased bone formation in areas of bone adjacent to myeloma cells. The mechanisms underlying osteolysis in multiple myeloma in vivo are unclear. We used a human plasma cell leukemia cell line, ARH-77, that has disseminated growth in mice with severe combined immunodeficiency (SCID) and expresses IgG kappa, as a model for human multiple myeloma, SCID mice were irradiated with 400 rads and mice were injected either with 10(6) ARH-77 cells intravenously (ARH-77 mice) or vehicle 24 hours after irradiation. Development of bone disease was assessed by blood ionized calcium levels, x-rays, and histology. All ARH-77, but none of control mice that survived irradiation, developed hind limb paralysis 28 to 35 days after injection and developed hypercalcemia (1.35 to 1.46 mmol/L) a mean of 5 days after becoming paraplegic. Lytic bone lesions were detected using x-rays in all the hypercalcemic mice examined. No lytic lesions or hypercalcemia developed in the controls. Controls or ARH-77 mice, after developing hypercalcemia, were then killed and bone marrow plasma from the long bones were obtained, concentrated, and assayed for bone-resorbing activity. Bone marrow plasma from ARH-77 mice induced significant bone resorption in the fetal rat long bone resorption assay when compared with controls (percentage of total 45Ca released = 35% +/- 4% v 11% +/- 1%). Histologic examination of tissues from the ARH-77 mice showed infiltration of myeloma cells in the liver and spleen and marked infiltration in vertebrae and long bones, with loss of bony trabeculae and increased OCL numbers. Interestingly, cultures of ARH-77 mouse bone marrow for early OCL precursors (colony-forming unit-granulocyte-macrophage [CFU-GM]) showed a threefold increase in CFU-GM from ARH-77 marrow versus controls (185 +/- 32 v 40 +/- 3 per 2 x 10(5) cell plated). Bone-resorbing human and murine cytokines such as interleukin-6 (IL-6), IL-1 alpha or beta, TGF-alpha, lymphotoxin, and TNF alpha were not significantly increased in ARH-77 mouse sera or marrow plasma, compared with control mice, although ARH-77 cells produce IL-6 and lymphotoxin in vitro. Conditioned media from ARH-77 cells induced significant bone resorption in the fetal rat long bone resorption assay when compared with untreated media (percentage of total 45Ca released = 22% +/- 2% v 11% +/- 1%). This effect was not blocked by anti-IL-6 or antilymphotoxin (percentage of total 45Ca released = 19% +/- 1% and 22% +/- 1%, respectively). Thus, we have developed a model of human multiple myeloma bone disease that should be very useful to dissect the pathogenesis of the bone destruction in multiple myeloma.

Underlying factor structure of perinatal events

The underlying factor structure of perinatal events was examined for 847 children (272 normals, 117 developmentally disabled, 37 speech disordered, 221 learning disordered, 91 emotionally disturbed, and 109 Head Start children). Pertinent perinatal information from the Maternal Perinatal Scale was subjected to a principle-components factor analysis. Ten factors accounting for some 58% of the total variance were isolated. In general, these factors appeared to be consistent with clinical evidence. The results were discussed in terms of their implications for the utility of perinatal information.

The immune system and major depression

This paper reviews research literature on the links between human immune functioning and mood disorders. It summarizes the initial steps of this fledgling research area since its inception in the late 1970s, and outlines a range of studies that are needed to increase our neuroimmunological sophistication. Future investigations will require greater specificity in several interrelated realms of inquiry: diagnostic, epidemiologic, and physiologic. In particular, this paper highlights basic physiological studies needed in both neurophysiology and immunology to provide a foundation for meaningful examination of their interface. Among the areas that require more specific investigation in both immunologic and mood disorders research is that of temporal organization. Just as psychiatric researchers have begun to scrutinize temporal cycles of mood, behavior, and neurophysiology, so too exploration of immune functioning must take into account predictable temporal cycles such as circadian and ultradian rhythms, as they shape responses to unanticipated external perturbations. Clarification of the temporal dimension will add significantly to our analysis of the links between immune functioning and mood disorders. The basic science of psychoneuroimmunology continues to mature, bringing new discoveries and revealing hitherto unknown mechanisms and interactions. This is a field of study in many ways still on the frontier, and explication of the long suspected links between mood disorders and immune functioning continues to beckon.

Role of beta-adrenergic receptor downregulation in the peak exercise response in patients with heart failure due to idiopathic dilated cardiomyopathy

The effect of beta-adrenergic receptor downregulation on peak exercise response in patients with heart failure has not been directly investigated. Seventy-two patients with idiopathic dilated cardiomyopathy who had a mean ejection fraction of 23 +/- 1% (mean +/- SEM) and New York Heart Association class II or III symptoms were investigated. Subjects underwent maximal exercise testing on a bicycle or a treadmill, hemodynamic assessment by right heart catheterization, and measurement of total beta-adrenergic receptor density by 125I-iodocyanopindolol binding performed in the right ventricular endomyocardial biopsy tissue and in peripheral lymphocytes. Endomyocardial biopsy beta-adrenergic receptor density (Bmax) was markedly decreased (45 +/- 2 fmol/mg), and significantly lower than lymphocytes Bmax (107 +/- 14 fmol/mg; p < 0.05). By univariate analysis, all exercise variables correlated significantly with biopsy tissue Bmax but not with lymphocyte Bmax. Maximal exercise oxygen consumption (VO2max) yielded the highest correlation with Bmax (r2 = 0.61, p < 0.001). By stepwise regression analysis, VO2 max, delta heart rate x systolic blood pressure, and ejection fraction were all independently related to Bmax. Myocardial beta-adrenergic receptor downregulation is likely to be partially responsible for the reduced chronotropic and inotropic responses to peak exercise in patients with mild to moderate symptomatic heart failure due to idiopathic dilated cardiomyopathy.

Factor analysis of the Halstead-Reitan Neuropsychological Test Battery for Older Children

Studies of the factor structure of the Halstead-Reitan Neuropsychological Test Battery for Older Children (HRNB-C) have reported solutions ranging from 5 to 7 constructs. The current study examined the underlying factor structure of the HRNB-C using only tests from the Battery itself with 800 learning disabled children. The results showed a four factor solution to be the most heuristic. These dimensions were identified as Speed of Operation, Tactile-Motor Integration, Attention, and Visuo-Spatial Memory. When ancillary tests are excluded it is argued that four factors provide the best description of the underlying structure of the HRNB-C.

Clinical studies with the new glycosylated recombinant prourokinase

Recombinant prourokinase (r-ProUK) is a single-chain urokinase-type plasminogen activator that is produced from a mammalian cell line. It is administered as a zymogen and remains inactive until converted to the active two-chain form on the surface of a clot. The clot specificity of this agent, therefore, is conferred by the site of conversion to the active form on the surface of the clot. Two pilot studies were conducted to evaluate the safety and efficacy of r-ProUK in patients with acute myocardial infarction. In the first study, the 90-minute patency rate was 66.7% in 21 patients receiving 60 mg over 60 minutes and 72.2% in 18 patients receiving 60 mg over 90 minutes. In the second study, the 90-minute patency rates were 45.5% in the group primed with recombinant urokinase who were given 60 mg of r-ProUK infused over 60 minutes (11 patients) and 80.8% in the primed group given 60 mg infused over 90 minutes (26 patients). Only 4.6% of patients experienced severe bleeding complications, with no patient developing intracranial hemorrhage. These two studies describe the first application of r-ProUK in patients. Although two doses were selected for evaluation, the small number of patients studied did not permit the selection of one dose as superior to the other. The results, however, did indicate that r-ProUK is a very effective thrombolytic agent in achieving patency of occluded coronary arteries. It is especially effective in maintaining coronary patency, having shown only a 1.4% rate of reocclusion. Serious bleeding complications were few and no intracranial hemorrhages were noted in this group of 131 patients. Additional clinical trials will be needed to compare the efficacy of r-ProUK with that of other available thrombolytic agents.

Incomplete recanalization as an important determinant of Thrombolysis in Myocardial Infarction (TIMI) grade 2 flow after thrombolytic therapy for acute myocardial infarction. TEAM Investigators. Thrombolytic Trial of Eminase in Acute Myocardial Infarction

The outcome of patients with Thrombolysis in Myocardial Infarction (TIMI) trial grade 2 flow is worse than that of patients with TIMI grade 3 flow after thrombolytic therapy for acute myocardial infarction. It is unclear whether TIMI grade 2 flow represents incomplete recanalization of the culprit lesion or poor distal runoff. The Thrombolytic Trial of Eminase (anistreplase) in Acute Myocardial Infarction (TEAM)-2 and TEAM-3 were randomized trials comparing anistreplase with streptokinase (TEAM-2, n = 370) or with alteplase (tissue plasminogen activator) (TEAM-3, n = 325). We compared the minimal luminal diameter of the culprit lesion in patients with TIMI grade 2 flow with that in patients with TIMI grade 3 flow both 90 minutes (TEAM-2) and 1 day (TEAM-3) after thrombolysis. Patients with TIMI grade 2 flow had a lower residual luminal diameter in the culprit lesion than patients with TIMI grade 3 flow (TEAM-2, 0.58 +/- 0.03 vs 0.79 +/- 0.02 mm, p = 0.0001; TEAM-3, 0.88 +/- 0.04 vs 1.17 +/- 0.03 mm, p = 0.0001, for patients with TIMI grades 2 and 3 flow). Residual percent stenosis was correspondingly higher in patients with TIMI grade 2 flow. At the early angiogram, 66% of patients with TIMI grade 2 flow, but only 35% of those with TIMI grade 3 flow, had a minimal luminal diameter of 0.6 mm (positive predictive value 87%, negative predictive value 35%). Incomplete recanalization of the culprit lesion may thus be an important determinant of TIMI grade 2 flow after thrombolysis. Whether more complete thrombolysis or rescue angioplasty improves outcome in these patients deserves evaluation.

Contemporary clinical trials in ventricular tachycardia and fibrillation: implications of ESVEM, CASCADE, and CASH for clinical management

Recent clinical trials in patients with ventricular tachycardia (VT) or fibrillation (VF) have occurred in the setting of the disappointing results of postinfarction secondary prevention studies using Class I antiarrhythmics (e.g., CAST). ESVEM addressed in a randomized trial whether electrophysiologic study (EPS) or Holter monitoring (HM) is a more accurate predictor of long-term antiarrhythmic drug efficacy in VT/VF patients (N=486) and what the relative efficacy of various antiarrhythmic agents is for VT/VF. Surprisingly, arrhythmia recurrence rates were not significantly different by the method of determining an efficacy prediction. However, arrhythmia recurrence and mortality were lower (by about 50% at 1 year) in patients treated with sotalol (a mixed Class II/III agent) than with other drugs (Class I). CASCADE evaluated empiric amiodarone versus guided (EPS or HM) standard (Class I) therapy in survivors of out-of-hospital cardiac arrest due to VF. The primary endpoint of cardiac death, resuscitated VF, or syncopal shock (in ICD patients) was reduced by amiodarone compared with conventional therapy (9% vs 23% at 1 year). An interim report of the ongoing CASH study suggested in 230 survivors of cardiac arrest that propafenone (Class IC) provided less effective prophylaxis (approximately 20% 1-year mortality) compared with randomly assigned therapies with amiodarone, metoprolol, or an ICD (approximately 14% mortality rates) and was excluded from further study. These studies have led to a paradigm shift in the approach to antiarrhythmic therapy of VT/VF: drugs with antisympathetic plus Class III (refractoriness prolonging) action (i.e., sotalol, amiodarone) are superior to traditional drugs with Class I( conduction slowing) effects, even when guided by EPS or HM.

Immune response factors in rheumatic heart disease: meta-analysis of HLA-DR associations and evaluation of additional class II alleles

OBJECTIVES

This study used a meta-analysis to examine HLA-DR frequencies in rheumatic heart disease and prospectively examined other class II allelic disease associations.

BACKGROUND

Studies of rheumatic heart disease have reported HLA class II allelic associations, but these are inconsistent.

METHODS

A meta-analysis combined all known (n = 10) studies to determine disease risk associated with HLA-DR antigen expression. Meta-analysis of studies grouped by ethnic derivation of subjects was also performed. The present study also examined DQA, DQB and DPB allele frequencies by DNA-based strategies.

RESULTS

Meta-analysis showed a significant negative disease association with DR5 (odds ratio [OR] 0.67, p < 0.00003) for all combined studies. Among black patients, DR1 was increased (OR 2.80, p < 0.004); DR6 was increased (OR, 2.03, p < 0.003); and DR 8 was decreased (OR 0.32, p < 0.02). Among Eastern Indian patients, DR3 was increased (OR 2.44, p < 0.00003), with decreased expression for DR2 (OR 0.31, p < 0.00001) and DR5 (OR 0.52, p < 0.05). DR4 was increased among American whites (OR 1.74, p < 0.03), although there was significant heterogeneity among studies of whites. DQA, DQB and DPB allele frequencies were similar for control subjects and patients.

CONCLUSIONS

Our findings support an association between major histocompatibility complex class II alleles and risk for rheumatic heart disease. However, heterogeneity in associations was observed among different ethnic and racial groups; regional and temporal differences in streptococcal outbreaks may compound this heterogeneity. Further studies are necessary to elucidate the respective contributions of these variables.

Time to arrhythmic, ischemic, and heart failure events: exploratory analyses to elucidate mechanisms of adverse drug effects in the Cardiac Arrhythmia Suppression Trial

In this study we investigated the time to the first arrhythmic, ischemic, or failure event for encainide-flecainide and moricizine versus their respective placebo comparison groups in the Cardiac Arrhythmia Suppression Trial. The purpose was to explore possible mechanisms for the excessive deaths associated with active therapy that have been previously reported. Differences were noted between the active drugs. In particular, encainide-flecainide appeared to convert an ischemic event into death in more cases and more promptly than moricizine. However, the excessive deaths noted on encainide-flecainide were as likely to occur subsequent to a failure event as an ischemic event; for both encainide-flecainide and moricizine, the vast majority of excess deaths appeared to be the result of an increase in arrhythmia events without any protective effect of the drug. We were unable to identify any specific mechanism to explain the adverse effect of encainide and flecainide.

Angiotensin-converting enzyme gene polymorphism is associated with myocardial infarction but not with development of coronary stenosis

BACKGROUND

Although both genetic and nongenetic factors contribute to the pathogenesis of coronary artery disease, the identification of specific genetic lesions has lagged behind the identification of critical environmental risk factors. A reported association between myocardial infarction (MI) and the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene in European men suggests a critical role for this genomic region. However, the generality of this association remains to be determined. It also is not clear at what stage in disease progression the association with the ACE I/D polymorphism becomes important.

METHODS AND RESULTS

We evaluated the ACE I/D polymorphism in patients who had undergone coronary angiography (402 men and 295 women) and in 203 representative control subjects. After polymerase chain reaction amplification, genotypes were determined by agarose gel sizing and by hybridization with allele-specific oligonucleotides. After patients were categorized by the degree of coronary artery stenosis and the occurrence of an MI, the distribution of ACE I/D genotypes was evaluated by log linear analysis. Patients were genetically representative of the regional population, and patients with > 60% stenosis of their coronary arteries had the same distribution of ACE I/D genotypes as did patients with < 10% stenosis. However, among patients with stenosis, the occurrence of an MI was significantly associated with the D allele in all patients (odds ratio [OR], 1.59; P = .002) and in men alone (OR, 1.63; P = .006). The lack of significance in women (OR, 1.40; P = .263) is probably due to the fact that only 36 women in the present study had experienced an MI. Furthermore, the association between MI and the ACE I/D polymorphism was independent of blood pressure, smoking habits, and body mass index.

CONCLUSIONS

Segregation of the ACE I/D polymorphism is a pervasive genetic risk factor for MI in whites but has no evident effect on the events leading to stenosis of the coronary arteries. This suggests that risk of MI is influenced by two independent processes--atherogenesis that leads to coronary stenosis followed by conversion to MI. The renin-angiotensin system appears to confer significant risk of infarction by influencing the conversion to MI but has no apparent effect on the development of atherostenosis.

A rapid and accurate method to realign PET scans utilizing image edge information

Movement during or between PET examinations is a common and serious problem. Consequently, there is a great need for rapid, accurate and robust methods to realign image sets.

METHODS

Derivative information from the image sets was used to extract areas containing edge information. Image similarity between a reference dataset and a misaligned dataset was evaluated for these areas. Powell's method for function minimization was used to find the set of translations and rotations along and around the axes that maximized image similarity. The method was validated by realigning image sets with a known misalignment. Image sets used for validation included brain studies using several different tracers and heart studies using labeled acetate or water.

RESULTS

The method was capable of labeled acetate or water.

RESULTS

The method was capable of realigning brain datasets using the same tracer with an accuracy of 0.2 mm and 0.2 degrees along and around all axes. The same accuracy was obtained for datasets with as few as a total of 800,000 counts. Brain studies utilizing different tracers with markedly dissimilar regional uptake patterns were realigned with an accuracy of 1.5 mm and 1.5 degrees. Heart studies using water or acetate were realigned with an accuracy of 0.2 mm and 0.4 degrees along and around all axes. Realignment of a heart study containing a large focal uptake defect against a dataset without defect produced errors no greater than 1.0 mm and 1.0 degree.

CONCLUSION

The use of derivative information provides a useful method to accurately realign PET image sets. It is rapid and noise-insensitive enough to allow for its routine use in dynamic studies.

Fractal clustering of ventricular ectopy correlates with sympathetic tone preceding ectopic beats

BACKGROUND

Fractal geometric analysis of ventricular ectopy yields a fractal dimension, which can range from zero to one and is inversely related to clustering of ventricular premature contractions (VPCs). Low values of this fractal dimension, which reflect significantly nonuniform distributions of ventricular ectopy, are found in patients with life-threatening ventricular arrhythmias and predict adverse outcomes in selected patients with congestive heart failure and with mitral regurgitation. However, the physiological mechanism and correlates of the fractal dimension are unknown.

METHODS AND RESULTS

To explore the physiological correlates of clustered ventricular ectopy, we studied 30 patients with a history of sustained ventricular tachycardia or ventricular fibrillation who had inducible sustained monomorphic ventricular tachycardia during electrophysiological study and also underwent drug-free 24-hour ambulatory ECG. In addition to fractal dimension (determined by use of our previously described algorithm), we measured the mean RR interval (+/- SD) for all sinus beats preceding a sinus beat and for all sinus beats preceding a single VPC and the mean root-mean-square difference (RMSSD) of all windows of 15 successive RR intervals (excluding ectopic beats) preceding a sinus beat and preceding a single VPC. Based on the directional changes of mean RR (a measure of both sympathetic and parasympathetic tone) and of RMSSD (a measure of parasympathetic tone), each patient's inferred relative sympathetic tone preceding ventricular ectopy was classified as increased, unchanged, or decreased. If these values changed concordantly, relative sympathetic tone was indeterminate. Fractal dimension did not correlate with the mean RR interval, SD of the RR interval, or RMSSD preceding sinus beats or preceding VPCs (all P > .10). In 20 patients, fractal dimension was significantly lower among those with increased relative sympathetic tone (n = 14) than those with unchanged or decreased sympathetic tone (n = 6, P = .008). Ten patients had indeterminate relative sympathetic tone.

CONCLUSIONS

Clustering of ventricular ectopy, as measured by the fractal dimension, is observed in patients at increased risk of sudden cardiac death. A low fractal dimension (clustered ventricular ectopy) is related to changes in heart rate and heart rate variability that are consistent with transient increases in cardiac sympathetic tone.

Electrophysiologic effects of antiarrhythmic drug therapy in the prediction of successful suppression of induced ventricular tachycardia

Predictors of a successful outcome of serial electrophysiologic (EP) and drug studies have been identified from among baseline patient characteristics but not from among measures of baseline and drug-related EP effects. Identifying such predictors would be useful in explaining the mechanism of successful drug therapy and in guiding drug development and selection. We prospectively studied EP characteristics in 159 trials in 62 patients with ventricular tachycardia or ventricular fibrillation during antiarrhythmic therapy and compared EP measures between successful (n = 30) and failed trials (n = 129). The average age of the patients was 64 years (range 27 to 78 years); 82% were men and 18% women; and 87% had coronary artery disease. Measurements included R-R, QRS, and QT intervals during intrinsic rhythm and during pacing at cycle lengths of 600 of 400 msec; ventricular effective refractory periods (ERP) during pacing at cycle lengths of 600 and 400 msec; and changes in these measures, comparing treatment with drug-free baseline. Univariate predictors of success (in order of significance) included ERP600/QRS600, sotalol versus other drugs, ERP400/QRS400, delta ERP600, delta R-R, ERP600, QRS400 (negative association), delta ERP400, QRS600 (negative association), ERP400 (all p < 0.1). In two separate multivariate models, one for each drive cycle length, only the ratio ERP600/QRS600 (p = 0.01) in the first model and ERP400/QRS400 (p = 0.01) in the second model were significantly and independently associated with achieving noninducibility with drug therapy. Therefore measures of greater refractoriness and lesser delays in conduction velocity (ie, greater "wavelength") relate to drug success.(ABSTRACT TRUNCATED AT 250 WORDS)

Interaction of baseline characteristics with the hazard of encainide, flecainide, and moricizine therapy in patients with myocardial infarction. A possible explanation for increased mortality in the Cardiac Arrhythmia Suppression Trial (CAST)

BACKGROUND

The Cardiac Arrhythmia Suppression Trial (CAST) was designed to test the hypothesis that suppression of ventricular ectopy with antiarrhythmic drugs after a myocardial infarction reduces the incidence of sudden arrhythmic death. Patients in whom ventricular ectopy could be suppressed with encainide, flecainide, or moricizine were randomly assigned to receive either active drug or placebo. The encainide and flecainide arms of the study were discontinued in 1989 (CAST-I) and the moricizine arm in 1991 (CAST-II) because of excess mortality. To explore the mechanisms of these adverse outcomes, we examined the interaction of baseline characteristics with the hazard of therapy with encainide, flecainide, or moricizine compared with their respective placebos.

METHODS AND RESULTS

CAST-I comprised 755 patients assigned to flecainide or encainide and 743 patients assigned to placebo, whereas in CAST-II, 502 patients received moricizine and 491 patients received placebo. Clinical and laboratory baseline variables of patients receiving active drug and those receiving placebo were similar. In CAST-I patients, there was a significant interaction of active therapy with both all-cause death/cardiac arrest and arrhythmic death/cardiac arrest for non-Q-wave myocardial infarction (total mortality hazard ratios, 1.8 versus 7.9 for Q-wave versus non-Q-wave infarction, P = .03). Ventricular premature depolarization (VPD) frequency > or = 50/h and heart rate > or = 74 beats per minute each interacted significantly with total mortality/cardiac arrest only. In the sicker CAST-II patients (ejection fraction < or = 40%), only diuretic use at baseline interacted significantly with moricizine use for both all-cause death/cardiac arrest and arrhythmic death/cardiac arrest (total mortality hazard ratios, 1.9 versus 0.7 for diuretic use versus no use, P = .01).

CONCLUSIONS

Although active treatment in CAST-I was associated with greater mortality than placebo with respect to almost all baseline variables, the therapeutic hazard was more than expected in patients with non-Q-wave myocardial infarction and (for total mortality) frequent premature VPDs and higher heart rates, suggesting that the adverse effect of encainide or flecainide therapy is greater when ischemic and electrical instability are present. The relative hazard of therapy with moricizine in the sicker CAST-II population was greater in those using diuretics. Thus, although these drugs have the common ability to suppress ventricular ectopy after myocardial infarction, their detrimental effects on survival may be mediated by different mechanisms in different populations, emphasizing the complex, poorly understood hazards associated with antiarrhythmic drug treatment.

Comparison of signal-averaging electrocardiographic systems using device specific criteria in 104 normal subjects

The advent of several signal-averaged electrocardiogram (SAECG) systems for late potential (LP) assessment warrants comparisons to assess intersystem reproducibility and variability. Simultaneous SAECGs on two systems, Arrhythmia Research Technology (ART) and Marquette (MEI), were performed on 104 normal volunteers (53 males, age 44 +/- 14 years), and analyzed filtered QRS duration (TFQRS), root mean square voltage (RMS40), and low amplitude signal duration (LAS40), filtered at 40-250 Hz. The Gomes criteria (TfQRS > 114 msec, RMS40 < 20 microV and LAS40 > 38 msec) were used as criteria for LP. The data was also analyzed using the recently proposed system specific criteria for MEI (TFQRS > 120 msec, RMS40 < 20 microV and LAS40 > 38 msec). Where appropriate, statistical analysis was performed using simple linear and Spearman's rank correlation, analysis of variance, Finn's R and McNemar's test.

RESULTS

The means +/- SD for ART and MEI were: TFQRS: 97.2 +/- 8.9 vs 108.2 +/- 7.2 msec (R = 0.76), RMS40: 31.8 +/- 17.8 vs 45.3 +/- 19.9 microV (R = 0.53), and LAS40: 32.2 +/- 8.4 vs 30 +/- 7.4 (R = 0.54). When the Gomes criteria were applied, the number of subjects identified by each system as abnormal were: TFQRS = 3 vs 22 (P < 0.001), RMS40 = 20 vs 8 (P = 0.004), LAS40 = 21 vs 9 (P = 0.004), TFQRS/RMS40 = 3 vs 6 (P = 0.38), TFQRS/LAS40 = 3 vs 7 (P = 0.22), RMS40/LAS40 40 = 17 vs 8 (P = 0.02), and all three criteria = 3 vs 6 (P = 0.38) for ART vs MEI, respectively. Percent agreement was 81.7% for TFQRS and 84.6% for RMS40 and LAS40 when single criteria were applied. Agreement improved when combined criteria were utilized (87.5%-95.2% for any two criteria and 95.2% for all three criteria). The intersystem agreement that was not due to chance was 0.63-0.69 for single criteria and 0.75-0.90 for combined criteria. Disagreement was highly significant for the three criteria when used singly and for RMS40 and LAS40 combined. Disagreement was not significant when TFQRS was used in combination with > or = one other criteria. When the MEI criteria were applied, there was a decrease in the number of subjects identified by the MEI system as abnormal, using the TFQRS criteria singly or in combination. Percent agreement for system specific TFQRS measurements was 94.2% for single criteria and 97.1% for combined criteria. The intersystem agreement that was not due to chance improved (88-0.94). Disagreement between system specific criteria for TFQRS was not significant (P > 0.05).

CONCLUSION

Our data indicate that although there is a general correlation between ART and MEI measurements, variability is substantial, leading to significant differences when the criteria for LP are applied, especially for single parameter determinations. Thus, there is a need to establish system specific normal ranges and more accurate criteria for LP parameters.

New recombinant glycosylated prourokinase for treatment of patients with acute myocardial infarction. Prourokinase Study Group

OBJECTIVES

Three dosage regimens of a new recombinant glycosylated prourokinase (A-74187) were evaluated by measuring coronary artery patency at 90 min in patients with acute myocardial infarction.

BACKGROUND

Prourokinase is a thrombolytic drug with unique pharmacologic properties that may be clinically advantageous.

METHODS

Aspirin (325 mg), intravenous heparin and prourokinase (60- or 80-mg monotherapy or 60 mg "primed" with a preceding bolus dose of 250,000 IU of recombinant urokinase) were administered to 128 patients. Coronary angiography was performed at 60 min (wherever possible), 90 min (primary end point) and 24 h to determine arterial patency and reocclusion rates. Plasma was collected serially to measure fibrinogen, plasminogen, thrombin antithrombin III and fibrinopeptide A. Clinical events until hospital discharge were recorded.

RESULTS

The coronary artery patency rate at 90 min was similar for all three regimens, averaging 73% (95% confidence interval [CI] 64% to 80%); Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow rates averaged 52% (95% CI 42% to 61%). Arterial patency at 60 min was 62% (95% CI 50% to 73%), and reocclusion occurred in 1.4% (95% CI 0.1% to 4.1%). Prourokinase demonstrated relative fibrin specificity at all doses studied. Fibrinopeptide A and thrombin antithrombin III levels were elevated at baseline and declined rapidly during the 1st 12 h. There was no difference in the baseline values of these thrombin markers between patients with patent versus closed arteries at 90 min. There was one death; no strokes occurred.

CONCLUSIONS

A-74187 prourokinase is a rapid-acting, effective fibrin-specific thrombolytic agent. Reocclusion was unusual, possibly because of aggressive anticoagulation with intravenous heparin or unique features of the drug. Full definition of the clinical effectiveness of this drug merits examination in future randomized trials evaluating clinical and angiographic effectiveness.

Major histocompatibility complex class II gene frequencies by serologic and deoxyribonucleic acid genomic typing in idiopathic dilated cardiomyopathy

Certain immunologic features associated with idiopathic dilated cardiomyopathy (IDC) suggest an infectious and/or autoimmune etiology. In this regard, an association between the major histocompatibility complex class II allele, DR4, and increased risk for IDC was previously identified. In the present report, 43 additional patients with IDC and 236 control subjects were studied for major histocompatibility class II allele associations. DR alleles were identified by microcytotoxicity. No significant differences between control subjects and patients with IDC were seen, although the frequency of DR4 was increased among patients. DR4 subtyping (n = 9) was performed by "dot blot" hybridization of allele-specific oligonucleotide probes to PCR-amplified genomic deoxyribonucleic acid. The DRB1*0401 and DRB1*0404 alleles were each found in 44% (n = 4) of patients with IDC, and DRB1*0407 was identified in 1 patient (11%). DQ and DP alleles were identified by restriction endonuclease codigestion of polymerase chain reaction-amplified deoxyribonucleic acid. The digested fragments were separated and identified by polyacrylamide gel electrophoresis. Differences between patients and control subjects were observed for DQA1*0501 (11% of patients vs 28% of control subjects, p < 0.05) and DQB1*0201 (13% patients vs 25% control subjects, p < 0.05). A modest difference was noted for DQA1*0301 (35% patients vs 23% control subjects, p = 0.08). These findings suggest a complex immune-related etiology for IDC that cannot be explained solely by the presence or absence of a single class II allele. However, this and other studies continue to implicate genes within the class II region in determining the risk for IDC.

Flecainide acetate for paroxysmal supraventricular tachyarrhythmias. The Flecainide Supraventricular Tachycardia Study Group

Flecainide has been shown to be effective in short-term, controlled studies for prevention of paroxysmal supraventricular tachycardia (SVT) and paroxysmal atrial fibrillation (AF). However, it is unknown whether this beneficial response is maintained during long-term chronic therapy. Forty-nine patients were studied who enrolled in double-blind, placebo-controlled, short-term studies of safety and efficacy and subsequently received long-term, open-label therapy for > or = 6 months (mean duration of therapy, 17 months). To evaluate chronic efficacy, events during long-term therapy were documented by a transtelephonic monitor for either 4 or 8 weeks, comparable to the corresponding 4- or 8-week placebo-baseline periods in the same patients. Results during chronic therapy were compared with those at baseline and after the initial (short-term) treatment period. Compared with placebo-baseline results, the number of patients free of arrhythmic attacks increased significantly for both patients with SVT (from 24% to 82%, p = 0.013, n = 17) and patients with AF (from 12% to 68%, p < 0.001, n = 25). Mean time to first attack and mean number of days between attacks also showed significant and parallel increases during the chronic efficacy period. In patients with paired short- and long-term efficacy evaluations with the same dose of flecainide, end points were maintained at equivalent levels or showed further improvement (i.e., mean rate of AF attacks decreased further with chronic therapy, p = 0.036). No proarrhythmic events, death, or myocardial infarction occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between cellular rejection of cardiac allografts and quantitative changes among T-cell subsets identified by V beta epitope expression

BACKGROUND

Cellular rejection of an allograft is mediated in part by peripheral blood T cells. We tested the hypothesis that quantitative changes in T-cell subsets can be detected in the peripheral blood and that these changes correlate with rejection.

METHODS AND RESULTS

T-cell subset analysis was performed by flow cytometry using monoclonal antibodies recognizing six isotypic epitopes of the T-cell receptor beta-chain variable (V) region. These analyses were done at 7-day (mean) time intervals. Fluctuations within a given subset were determined by dividing the number of positive cells observed by the number of positive cells found on the previous analysis. For healthy volunteers observed over a period of 30 days, 119 of 120 subset ratios (99.2%) fell between 0.5 and 2.0. For patients, 57 of 240 subset ratios (23.8%) fell outside of this range (P < .004, chi 2). The occurrence of the abnormal ratios coincided more closely with cellular rejection (mean +/- SD, 7.7 +/- 6.2 days from a positive biopsy; median, 5 days; range, 0 to 28 days) than did the occurrence of normal subset ratios (mean +/- SD, 14.4 +/- 10.9 days from a positive biopsy; median, 11 days; range, 0 to 44 days; P < .005 by Mann-Whitney U test). Regression analysis confirmed a significant (P < .001, R = .91) temporal association between cellular rejection and abnormal subset fluctuations. No correlation was found between abnormal subset ratios and either vascular rejection or use of high-dose prednisone.

CONCLUSIONS

T-cell subset measurement may be a method of noninvasive monitoring of cellular rejection after transplantation and may provide insights into the physiology of graft rejection with the potential for the development of more specific immunosuppressive therapy.

Reduction in QT interval dispersion by successful thrombolytic therapy in acute myocardial infarction. TEAM-2 Study Investigators

BACKGROUND

QT dispersion (QTd, equals maximal minus minimal QT interval) on a standard ECG has been shown to reflect regional variations in ventricular repolarization and is significantly greater in patients with than in those without arrhythmic events.

METHODS AND RESULTS

To assess the effect of thrombolytic therapy on QTd, we studied 244 patients (196 men; mean age, 57 +/- 10 years) with acute myocardial infarction (AMI) who were treated with streptokinase (n = 115) or anistreplase (n = 129) at an average of 2.6 hours after symptom onset. Angiograms at 2.4 +/- 1 hours after thrombolytic therapy showed reperfusion (TIMI grade > or = 2) in 75% of patients. QT was measured in 10 +/- 2 leads at 9 +/- 5 days after AMI by using a computerized analysis program interfaced with a digitizer. QTd, QRSd, JT (QT minus QRS), and JT dispersion (JTd, equals maximal minus minimal JT interval) were calculated with a computer. There were significant differences in QTd (96 +/- 31, 88 +/- 25, 60 +/- 22, and 52 +/- 19 milliseconds; P < or = .0001) and in JTd (97 +/- 32, 88 +/- 31, 63 +/- 23, and 58 +/- 21 milliseconds; P = .0001) but not in QRSd (25 +/- 10, 22 +/- 7, 28 +/- 9, and 24 +/- 9 milliseconds; P = .24) among perfusion grades 0, 1, 2, and 3, respectively. Similar results were obtained comparing TIMI grades 0/1 with 2/3 and 0/1/2 with 3. Patients with left anterior descending (versus right and left circumflex) coronary artery occlusion showed significantly greater QTd (70 +/- 29 versus 59 +/- 27 milliseconds, P = .003) and JTd (74 +/- 30 versus 63 +/- 27 milliseconds, P = .004). Similarly, patients with anterior (versus inferior/lateral) AMI showed significantly greater QTd (69 +/- 30 versus 59 +/- 27 milliseconds, P = .006) and JTd (73 +/- 30 versus 63 +/- 27 milliseconds, P = .007). Results did not change when Bazett's QTc or JTc was substituted for QT or JT or when ANOVA included adjustments for age, sex, drug assignment, infarct site, infarct vessel, and number of measurable leads. On ANCOVA, the relation of QTd or JTd and perfusion grade was not influenced by heart rate.

CONCLUSIONS

Successful thrombolysis is associated with less QTd and JTd in post-AMI patients. The results are equally significant when either QT or JT is used for analysis. These data support the hypothesis that QTd after AMI depends on reperfusion status as well as infarct site and size. Reduction in QTd and its corresponding risk of ventricular arrhythmia may be mechanisms of benefit of thrombolytic therapy.

Differences in sodium and D-glucose transport between hamster and rat lungs

The purpose of this study was to characterize phloridzin- and amiloride-sensitive transport across blood-gas barrier of hamster and rat lungs. Air spaces of isolated perfused lungs were instilled with a solution containing 22Na or L-[3H]glucose, D-[14C]glucose, and fluorescein isothiocyanate-labeled dextran. Apparent permeability-surface area products (PS) were calculated. Phloridzin (Na(+)-dependent D-glucose transport inhibitor) had no effect on D-glucose or sodium transport out of air spaces in hamster lungs. In contrast, in rat lungs, phloridzin decreased PS for D-glucose by 89% and that for Na by 28%. Trapping of 14CO2 in vascular samples was measured to estimate metabolism. Unlabeled air space D-glucose increased appearance of perfused D-[14C]glucose in air spaces of rat lungs. We conclude that Na(+)-dependent D-glucose transport is important for D-glucose uptake in rat lungs but not in hamster lungs. In hamster lungs, amiloride (Na+ transport inhibitor) also decreased PS for sodium, but drugs known to stimulate sodium transport in rat lungs had no effect. Thus, species differences in active transport processes exist in the distal air spaces of mammalian lungs.

Sleep in fall/winter seasonal affective disorder: effects of light and changing seasons

Disturbances of sleep are a hallmark of seasonal affective disorders (SAD), as they are of other mood disorders. Fall/winter SAD patients most often report hypersomnia. Among responses of 293 SAD patients on a symptom questionnaire, complaints of winter hypersomnia (80%) greatly exceeded insomnia (10%), hypersomnia plus insomnia (5%), or no sleep difficulty (5%). Increased sleep length in fall/winter is not unique to SAD. Among 1571 individuals across four latitudes surveyed at random from the general population, winter sleep increases of < or = 2 hr/day relative to summer were reported by nearly half. However, hypersomnia had a low correlation (r = 0.29) with the total number of other SAD symptoms that were reported in this sample. Ten SAD patients kept daily sleep logs across 1 yr that showed increases in fall and winter (sleeping most in October; least in May) whose maximum averaged 2.7 hr per day more weekend sleep than in spring and summer. These winter increases might have been somewhat attenuated since most received light therapy during part of the winter. Nocturnal EEG recordings of depressed SAD patients in winter showed decreased sleep efficiency, decreased delta sleep percentage, and increased REM density (but normal REM latency) in comparison with recordings: (1) from themselves in summer; (2) from themselves after > or = 9 days of light therapy; or (3) from age- and gender-matched healthy controls. Thus, the extent of fall/winter oversleeping recorded by our SAD patients did not differ dramatically from that reported by the general population, but sleep complaints of our SAD patients have been accompanied by features of sleep architecture that are different from healthy controls and are reversed by summer or by bright-light therapy.

Histoincompatibility-associated differences in the phenotypes of murine cardiac allograft infiltrating T cells

Mechanisms of graft rejection may be governed in part by the kind and degree of histocompatibility differences between donor and recipient. Cardiac allograft rejection was studied in three murine models selected to provide disparity at different major histocompatibility complex (MHC), minor lymphocyte stimulating (Mls) and other minor histocompatibility loci. Graft survival for the A.TL to A.TH combination (M3) was significantly longer (median day of rejection 15.0 days) than both the B10.A to AKR (M2) or the C57BL/6 to C3H/HeN (M1) donor-recipient combinations (median days of rejection: 9.0 days and 9.0 days respectively; P < 0.001). The infiltration of grafts by T cells was examined by removal of grafts serially post-transplantation and culturing mechanically disrupted graft tissue with interleukin-2 (IL-2). Recovery of T cells by this method revealed highly reproducible characteristics (kinetic and phenotypic), unique to each donor-recipient combination. Cultures from M1 and M2 grafts had differing CD4/CD8 T-cell ratios at days 2 (1.8 versus 0.7, respectively) and 4 (1.6 versus 0.1, respectively) post-transplantation. The M3 model differed from M2 (at days 4, 8 and 10) and from M1 (at days 8 and 10). At these times, cultures of M3 grafts contained a significantly increased percentage of CD4 cells and significantly decreased percentage of CD8 cells (CD4/CD8 ratios 0.9-1.3) by comparison with M1 (CD4/CD8 ratios 0.02-0.04) and M2 (CD4/CD8 ratios 0.1-0.02). Long-surviving M3 grafts (greater than 30 days post-transplantation) were compared with grafts removed immediately upon cessation of graft function (days 14, 15 and 18 post-transplantation). There was a significant difference between these groups in the ratios of CD4/CD8 T-cell ratios (1.1 versus 0.4, respectively). This study suggests that the cellular rejection mechanism of a graft is a variable process driven by the individual histocompatibility antigen disparity between donor and recipient. These findings may have diagnostic and therapeutic applications in organ transplantation.